/* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package java.util.prefs;
import java.io.File;
import java.io.FilenameFilter;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Properties;
import java.util.Set;
import org.apache.harmony.prefs.internal.nls.Messages;
/**
* The default implementation of <code>AbstractPreferences</code> for the Linux
* platform, using the file system as its back end.
*
* TODO some sync mechanism with backend, Performance - check file edit date
*
* @since 1.4
*/
class FilePreferencesImpl extends AbstractPreferences {
/*
* --------------------------------------------------------------
* Class fields
* --------------------------------------------------------------
*/
//prefs file name
private static final String PREFS_FILE_NAME = "prefs.xml"; //$NON-NLS-1$
//home directory for user prefs
private static String USER_HOME;
//home directory for system prefs
private static String SYSTEM_HOME;
/*
* --------------------------------------------------------------
* Class initializer
* --------------------------------------------------------------
*/
static {
AccessController.doPrivileged(new PrivilegedAction<Void>() {
public Void run() {
USER_HOME = System.getProperty("user.home") + "/.java/.userPrefs";//$NON-NLS-1$ //$NON-NLS-2$
SYSTEM_HOME = System.getProperty("java.home") + "/.systemPrefs";//$NON-NLS-1$//$NON-NLS-2$
return null;
}
});
}
/*
* --------------------------------------------------------------
* Instance fields
* --------------------------------------------------------------
*/
//file path for this preferences node
private String path;
//internal cache for prefs key-value pair
private Properties prefs;
//file represents this preferences node
private File prefsFile;
//parent dir for this preferences node
private File dir;
//cache for removed prefs key-value pair
private Set<String> removed = new HashSet<String>();
//cache for updated prefs key-value pair
private Set<String> updated = new HashSet<String>();
/*
* --------------------------------------------------------------
* Constructors
* --------------------------------------------------------------
*/
/**
* Construct root <code>FilePreferencesImpl</code> instance, construct
* user root if userNode is true, system root otherwise
*/
FilePreferencesImpl(boolean userNode) {
super(null, ""); //$NON-NLS-1$
this.userNode = userNode;
path = userNode ? USER_HOME : SYSTEM_HOME;
initPrefs();
}
/**
* Construct a prefs using given parent and given name
*/
private FilePreferencesImpl(AbstractPreferences parent, String name) {
super(parent, name);
path = ((FilePreferencesImpl) parent).path + File.separator + name;
initPrefs();
}
private void initPrefs() {
dir = new File(path);
newNode = (AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
public Boolean run() {
return Boolean.valueOf(!dir.exists());
}
})).booleanValue();
prefsFile = new File(path + File.separator + PREFS_FILE_NAME);
prefs = XMLParser.loadFilePrefs(prefsFile);
}
@Override
protected String[] childrenNamesSpi() throws BackingStoreException {
String[] names = AccessController
.doPrivileged(new PrivilegedAction<String[]>() {
public String[] run() {
return dir.list(new FilenameFilter() {
public boolean accept(File parent, String name) {
return new File(path + File.separator + name).isDirectory();
}
});
}
});
if (null == names) {// file is not a directory, exception case
// prefs.3=Cannot get children names for {0}!
throw new BackingStoreException(
Messages.getString("prefs.3", toString())); //$NON-NLS-1$
}
return names;
}
@Override
protected AbstractPreferences childSpi(String name) {
FilePreferencesImpl child = new FilePreferencesImpl(this, name);
return child;
}
@Override
protected void flushSpi() throws BackingStoreException {
try {
//if removed, return
if(isRemoved()){
return;
}
// reload
Properties currentPrefs = XMLParser.loadFilePrefs(prefsFile);
// merge
Iterator<String> it = removed.iterator();
while (it.hasNext()) {
currentPrefs.remove(it.next());
}
removed.clear();
it = updated.iterator();
while (it.hasNext()) {
Object key = it.next();
currentPrefs.put(key, prefs.get(key));
}
updated.clear();
// flush
prefs = currentPrefs;
XMLParser.flushFilePrefs(prefsFile, prefs);
} catch (Exception e) {
throw new BackingStoreException(e);
}
}
@Override
protected String getSpi(String key) {
try {
if (null == prefs) {
prefs = XMLParser.loadFilePrefs(prefsFile);
}
return prefs.getProperty(key);
} catch (Exception e) {
// if Exception happened, return null
return null;
}
}
@Override
protected String[] keysSpi() throws BackingStoreException {
final Set<Object> ks = prefs.keySet();
return ks.toArray(new String[ks.size()]);
}
@Override
protected void putSpi(String name, String value) {
prefs.setProperty(name, value);
updated.add(name);
}
@Override
protected void removeNodeSpi() throws BackingStoreException {
boolean removeSucceed = (AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
public Boolean run() {
prefsFile.delete();
return Boolean.valueOf(dir.delete());
}
})).booleanValue();
if (!removeSucceed) {
// prefs.4=Cannot remove {0}!
throw new BackingStoreException(Messages.getString("prefs.4", toString())); //$NON-NLS-1$
}
}
@Override
protected void removeSpi(String key) {
prefs.remove(key);
updated.remove(key);
removed.add(key);
}
@Override
protected void syncSpi() throws BackingStoreException {
flushSpi();
}
}